Tagisochrones

Short answer: To provide more shoppers for the local businesses. Read on for the longer answer.

Over on Chicago Cityscape I added a new feature called “market analysis” which measures the number of people who live within specific walking areas (measured by time) and driving areas (measured by distance).

I am in favor of removing apartment & condo bans in Chicago, especially in areas where they were previously allowed and near train stations.

Jefferson Park is centered around two co-located train stations, serviced by CTA and Metra respectively. There have been multiple proposals for multi-family housing near the stations (collectively called the Jefferson Park Transit Center) and some have been approved.

Always, however, there are residents who resist these proposals and the number of originally proposed apartments or condos gets reduced in the final version (classic NIMBYism).

There’re four reasons – at least – why more housing should be allowed near the Jefferson Park Transit Center:

Locally owned businesses require a significant amount of shoppers who live nearby and walk up traffic

More people should have the opportunity to live near low-cost transportation

It will include more affordable housing, through Chicago’s inclusionary zoning rules (the Affordable Requirements Ordinance, ARO)

There will be less driving, and therefore lower household transportation costs and less neighborhood pollution

To support the first reason, I used the “market analysis” tool to see just how many people live in a walkable area centered around Veterans Square, a mixed-use office and retail development adjacent to the train stations.

Comparatively, 19,707 people live within a 10 minute walk to The Crotch, or the center of Wicker Park, at the intersection of Milwaukee/North/Damen (get the Address Snapshot). The Blue Line station is about 75 feet south of the center point.

I would grant the low Veterans Square number a small discount based on the proximity to the Kennedy Expressway, which severely truncates walking areas up and down the northwest side. Still, even with that discount, ending up with less than half the amount as the one in Wicker Park, is disturbing. Wicker Park is hardly characterized by high-density housing. In fact, all of the new high-rises are just outside the 10 minute walk shed!

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The dark pink shows areas you can get to within 45 minutes by transit, and the light pink shows you how far you can get within 60 minutes of transit. The transit shed without the Red Line is much smaller!

I virtually dismantled the Red Line to show how important it is to get around the North Side via transit.

Mapzen, a fantastic company that makes free and open source mapping tools, and for whom I’m an independent contractor, updated its Mobility Explorer map to show where you can go from any point in a city by transit if a piece of existing transit infrastructure didn’t exist.

So, I handily took out the Red Line – the Chicago workhorse, carrying 145,000 people each weekday north of State/Lake station. The map shows the analysis, called an isochrone, as if you were departing from the Wilson station in Uptown.

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Mapzen* released Mobility Explorer last week. It is the graphical user interface (GUI) to the Transitland datastore of a lot of the world’s transit schedules and maps.

It also has isochrones, which are more commonly known as “mode sheds”, or the area that you can reach by a specific mode in a specific amount of time.

I wanted to test it quickly to see what these mode sheds say about where I live, a block north of Humboldt Park. From my house, on a bicycle, I can reach the edges of an area that’s 25 square miles in 15 minutes.

The distance you can travel from my house at the north end of Humboldt Park in 15 minutes by three modes, assuming you leave at 2:21 PM today (in increasing distance/area): Transit (dark purple) Bicycling (burgundy) Driving (pink)

You can request these isochrones through this API call for any location and they’ll be returned as GeoJSON.

I’m still learning how isochrones work, and how they can be adjusted (to account for different rider seeds and route costs or penalties). One difference between bicycling and driving is that the driving area is increased by expressways while the bicycling area has a more uniform shape.

The bike shed is 25.7 square miles, and the driving shed is 52.0 square miles.

*I do contract work for Mapzen and maintain parts of the Transitland Feed Registry.